The largest identified man-made environmental catastropheRichard Wilson, D Phil., Harvard UniversityPresented at the Royal Geographical Society9 am Wednesday August 29th 2007plus corrections and clarificationsAbstract:The problem of arsenic in South East Asia, particularly Bangladesh is the largest identified man made environmental catastrophe. The catastrophe demands three simultaneous actions.(1) Understanding the causes of the catastrophe; (a) why was arsenic present;(b) why was it made available in drinking water?; and(c) why did no one recognize what was happening in time to avert the catastrophe?(2) What exactly is the effect on humans of arsenic in the amounts present in the drinking water?(3) How can one rapidly bring pure water to the population to avoid further damage? and a fourth question which is less urgent but crucially important.(4) How can the world avoid such catastrophes in the future whether from arsenic or from some presently unknown cause?The first three were posed at an International meeting in Dhaka in 1998. I will review the appalling lack of progress in these, especially in item (3) with which I am most familiar.IntroductionIn Bangladesh at the turn of the century there were 60 million people who were drinking water at levels higher than the US EPA standard, and that in a tropical country where water intake is large. As a result many people developed dyspigmentation, (figure 1), keratoses (figure 2) , and skin cancers (Bowen’s disease in figure 3). If villagers walk on feet with keratoses they develop gangrene (figure 4) and a foot has to be removed. Internal cancers, bladder, kidney and lung are anticipated in due course. These will be discussed by Alan Smith latter in this session. Estimates vary, but over a million people will have adverse health symptoms before the problem is solved, and between 100,000 and 1,000,000 will die. This exceeds by over tenfold the Chernobyl catastrophe, where less than 100 died outright and 1,200 children developed thyroid cancer, of which only 20 have proven fatal. Calculations predict that there will be 5,000 fatal cancers from Chernobyl in Belarus, Ukraine and Russia and perhaps 20,000 world wide. When other regions, West Bengal, Bihar, and Nepal etc are added in the comparison is even more dramatic.The Bangladesh catastrophe need not have happened and can therefore be called man-made as much as Chernobyl. Traditionally most Bangladeshis used surface waters. It was world agencies, World Bank, UNICEF and British Geological Survey that encouraged a switch to ground water, and 10 million tube wells had been dug before there were serious searches for arsenic. There was a lawsuit, being discussed later in this meeting, against the parent of British Geological Survey. I am not a proponent of lawsuits in these situations, largely because theblame, if blame is indeed appropriate, should be assigned wider than the above three organizations. The world toxicological community was silent while the wells were being dug. I include myself in that category. To their credit, the World Bank, UNICEF and the British Government have reacted positively to help. I call upon the whole world scientific community to help also. The prior informationArsenic has been known to be acutely poisonous for 3 millenia, but it was not realized to be dangerous at chronic (low repeated) doses. Following the Paracelsus’ maxim that “the dose makes the poison”. Dr Fowler of Edinburgh recommended low doses for stomach upsets about 1788. Fowler’s solution is in the British Pharmocopeia. At intermediate doeses, arsenic has been used as a cure for syphilis before peniciin was produced, and as a cure for leukemia. Beforechlorinated hydrocarbos were used, 1970, the USA sprayed 20,000 tons of arsenic a year on our crops and forgot about it. But warnings began to appear. Hutchinson in 1888 reported, in a prestigious British Journal, dyspigmentation, keratoses and cancers from continuous doses of Fowler’s solution. One such is shown in Figure 5. The famous epidemiologist Sir Richard Doll informed me that many years ago his father got cancer from continued use of Fowler’s solution. Then in 1895 arsenic was sprayed on vineyards in France and vineyard workers developed lung cancer. About 1903 there was the Manchester beer epidemic where beer had been made from arsenic contaminated water near Manchester and many ailments resulted. Notably, a Royal Commission reported on this, chaired by one of the brightest scientists of the 19th century, Lord Kelvin. In the 1920s arsenic was found in air pollution from smelters, and was shown to cause lung cancer. Also in the 1960s, a rare liver tumor, angiosarcoma was found in farmers. There were also reports of an incident in Japan where some cancers were found more than background but the number was small. In 1966 C.J.Chen showed that in an area of Taiwan NE of Tainan, that death rates from internal cancers were 100 times more probable than the US EPA calculation. Allof these were IGNORED or attributed to lung ingestion, and/or a threshold process. Indeed the US EPA only proposed a modification in the arsenic standard 14 years later! But I suggest a fourth (unstated) reason they were ignored is that rats and mice did not get cancer at appropriate doses. For most of the 20th century toxicologists had depended on rats and mice to give them warning of impending human problems. Moreover dogs, a species closer to man than rats and mice thrived on arsenic. It gave a sheen to theiir coats. Chickens are still fed arsenic as a growthenhancer in their feed. . But this time the comparison method method failed. We did not notice.The realizationIt is convenient to consider the first of three International Conferences and subsequent smaller ones, on Arsenic, held jointly by the Dhaka Community Hospital (DCH) and SOES, Jadavpur University, Kolkata, in February 1998, as a turning point in public attention to the arsenic problem. The 200 participants saw over 165 victims of chronic arsenic poisoning which number is more than most US dermatologists see in a lifetime. Most of the participants added a strong emotional reaction “we must do something” to their intellectual curiosity. The following general observations were made in a “Dhaka Declaration” at the end of the 1998 conference:1.) The groundwater of a significantly large area in Bangladesh is